Most of the Indian pharma stocks are trading in red with Panacea biotech and Dishman pharma being the leading underperformers. Forest Laboratories, a US based company has filed litigation against some generic companies including Lupin Ltd and Ranbaxy laboratories. The lawsuits are filed in the US district court of Delware, for infringing the patents which relates to its drug Savella tablets (Milnacipran hydrochloride). The patents in issue are patent number'342 and '220, set to expire in Nov 2021 and Sept 2029 respectively. The innovator of the drug, Forest laboratories has sued the generic companies within 45 days of stipulated time frame. This means the generic company's approval is stayed at least for 30 months beginning from the date of litigation filed. The other companies involved in this patent infringement case include US generic companies viz Par pharma, Mylan, Apotex and Hetero, USA. Which of these companies are among the first to file is still not known. The annual sales of Savella are $ 103 m. Lupin and Ranbaxy are trading down by 0.77% and 0.9% respectively.